A study of the bulk modulus and shear modulus of a Lake Agassiz clay

Abstract:

The bulk modulus and shear modulus of the Lake Agassiz Clay were studied in this thesis. The approach used in the study was to separate the stress system into volumetric and deviatoric components of stress. The bulk modulus is related to the volumetric behavior of the soil. The shear modulus is related to the deviatoric stress and to the level of mean normal stress. Thus the bulk modulus and shear modulus can be related to separate physical stress components. These relationships vary with the soil investigated. The bulk modulus of the Agassiz Clay was determined from isotropic compression tests... The shear modulus of the Agassiz Clay was determined from drained triaxial texts which were run at a constant mean normal stress. A total of fifteen drained triaxial tests were run at various levels of mean normal stress. The slope of the deviatoric stress strain curve defines the shear modulus G. ... Curves of mean normal stress versus deviatoric stress at failure were plotted for samples from the same soil. These curves constitute a unique failure theory. Expressions relating the mean normal stress and the deviatoric stress at failure were developed from this unique straight line relationship. It is concluded the the separation of volumetric and deviatoric components is a useful way of describing the stress system. The bulk modulus and shear modulus of a given soil can be satisfactorily determined by the use of the volumetric and deviatoric components.